By Blake Jackson
Recent reports from Pennsylvania fields show that wheat and barley, once appearing healthy in early June, are now showing signs of disease and quality concerns.
The recent cool, wet weather has encouraged the development of rust, leaf spots, powdery mildew, and head infections like scab, blotches, and sooty mold.
If you haven’t inspected your fields lately, now is an ideal time to assess late-season diseases, as this information will be vital for harvest decisions.
Why do fields treated for Fusarium head blight (scab) have fewer leaf diseases? Many growers have noticed that fungicide applications aimed at controlling scab during flowering also reduce other fungal diseases affecting the flag leaf. Although the primary goal is to manage scab, these sprays often help limit multiple diseases as harvest approaches.
Barley crops seem to be healthier compared to wheat. While barley is also susceptible to Fusarium graminearum infection during flowering, it possesses a natural resistance known as "Type II resistance," which restricts the fungus from spreading throughout the head. This means barley infections tend to stay localized, unlike wheat, where the fungus spreads more extensively.
Preventing all disease damage is challenging, especially with favorable weather conditions for fungal growth. Even resistant varieties and timely fungicide use cannot guarantee full protection.
As harvest nears, steps can be taken to minimize further damage. Delaying harvest to reach ideal moisture can allow diseases to worsen and mycotoxins to develop. Harvesting promptly and drying grain to below 15% moisture (13% for long-term storage) at 50°F helps stop deterioration.
If scab affects 25% or more of the heads, contact your insurance company about mycotoxin testing or claims before harvest. Consider separating grain from heavily infected fields to protect unaffected grain quality.
During harvest, adjusting combine settings to remove lighter, diseased kernels can improve grain quality. Studies recommend specific fan speeds and shutter openings to reduce discounts and increase profits.
For 2026, avoid rotating heavily scabbed fields into corn or grassy forages, especially with no-till residue. Opt for broadleaf crops like soybeans or alfalfa to reduce disease carryover.
Choosing varieties with moderate resistance and applying fungicides properly will help ensure better grain quality under disease-prone conditions.
Photo Credit: gettyimages-milos-cirkovic
Categories: Pennsylvania, Crops, Wheat